1. Field of the Invention
The present invention relates to a clamp mechanism for a disk drive suitable for use in an optical disk drive and the like.
2. Description of the Prior Art
A clamp mechanism for a conventional disk drive will be explained with reference to FIG. 10 and FIG. 11. A support member 51 is comprised of a chassis 52 including a hole 52a on the center thereof and a bent part 52b with a section of L-letter shape, and a support plate 53 having a magnetic plate 63, fixed to the chassis 52 so as to cover an upper hole of the chassis 52.
And, between the chassis 52 and the support plate 53 is made up a housing space 54.
A clamper 55 is comprised of a clamping part 55a made of a synthetic resin being a non-magnetic material, a neck part 55b formed integrally with the clamping part 55a, which has a smaller diameter than the clamping part 55a, a flange part 55c affixed to the neck part 55b, and a magnet 56 placed inside thereof.
And, the neck part 55b is inserted through the hole 52a of the chassis 52, the flange part 55c is contained in the housing space 54, the clamping part 55a is suspended on the lower part of the chassis 52, and the flange part 55c is suspended on the upper part of the chassis 52; and the clamper 55 is made vertically movable to the chassis 52.
A cushioning member 57 is made of a ring rubber or the like, and the cushioning member 57 is attached on the support plate 53 inside the housing space 54.
And, the clamper 55 is placed on the upper part, since the magnet 56 is attracted by the magnetic plate 63. In this state, the flange part 55c is in contact with the cushioning member 57, which functions as a shock absorber when the clamper 55 moves upward.
A drive member 58 is comprised of a drive plate 59 of which one end is rotatably supported and the other end is made vertically movable, a vertically movable motor 60 fixed to the other end of the drive plate 59, and a turntable 61 set about a spindle 60a of the motor 60, which is vertically movable together with the motor 60.
And, the turntable 61 is provided with a magnetic plate 61a on the upper side thereof, and when the turntable 61 moves up, the magnet 56 of the clamper 55 makes a transition from attraction with the magnetic plate 63 on the support plate 53 to attraction with the magnetic plate 61a. 
A mount member 62 is made of a metal plate having a hole 62a. The mount member 62 is placed between the clamper 55 and the turntable 61 to mount a disk D.
Next, the operation of the conventional clamp mechanism for a disk drive will be discussed. In the non-clamped state in FIG. 10, the clamper 55 is located on the upper part where the magnet 56 is attracted by the magnetic plate 63, and the turntable 61 is located on lower part.
First, in this state, the disk D is carried to the drive member 58 from a package or the like by a carrying member (not illustrated), and it is mounted on the mount member 62, as shown in FIG. 10.
Then, a drive motor (not illustrated) is driven to rotate the drive plate 59 so as to raise the other end upward.
And, as shown in FIG. 11, the turntable 61 moves upward with the disk D, and as the turntable 61 approaches the clamper 55, the clamper 55 is detached from attraction with the magnetic plate 63 into attraction with the magnetic plate 61a on the turntable 61. As a result, the disk D is clamped between the clamper 55 and the turntable 61.
Next, as the motor 60 is driven to rotate the spindle 60a, the disk D is turned through the turntable 61, thus performing reproduction or recording.
When dismounting the disk D to replace by another, first an eject button is pressed.
Then, the drive motor is driven to move the other end of the drive plate 59 downward, and accordingly the turntable 61 moves down together with the clamper 55.
And, the clamper 55 is suspended such that the flange part 55c is hung on the bent part 52b of the chassis 52. In this state, as the turntable 61 moves down further, the turntable 61 with the disk D goes down, and the attraction between the turntable 61 and the clamper 55 is released.
As the result, as shown in FIG. 10, the clamper 55 returns to the state of being attracted to the magnetic plate 63 by the magnet 56, and the turntable 61 is located downward to restore the initial state that the disk D is mounted on the mount member 62.
Then, the disk D is to be carried by the carrying member outside the drive member 58.
In the clamp mechanism for a conventional disk drive thus described, since the clamper 55 is attracted by the magnetic plate 63 in the non-clamped state of the disk D, if the disk drive receives vibrations and shocks, the clamper 55 will be released from attraction with the magnetic plate 63, thus creating displacement of the clamper 55, which is a problem to be resolved.
Further, the conventional clamp mechanism requires the support plate 53, magnetic plate 63, and cushioning member 57, etc., which increases not only the number of the components but also the production cost, and deteriorates the productivity.
As the first means to solve the aforementioned problems, the clamp mechanism for a disk drive of the present invention is configured with a turntable placed to be vertically movable, a clamper facing to the turntable, which is mounted on a support member such as a chassis so as to be movable in a direction of approaching and detaching from the turntable, and a holding arm that can be engaged with and released from the clamper, wherein the turntable and the clamper are made to be attracted to each other by a magnetic force, the holding arm releases the clamper from a lifted-up state when the turntable is lifted up, a disk is clamped between the turntable and the clamper by attraction of the turntable and the clamper by the magnetic force, the disk is released from being clamped when the turntable is lowered, and the holding arm lifts up the clamper to maintain the lifted-up state of the clamper.
As the second means to solve the problems, the clamp mechanism is configured such that the clamper is attached perforating through the support member, and is provided with a clamping part that underlies the support member and a flange part that overlies the support member, and the holding arm lifts up the flange part to press the flange part to the support member.
As the third means to solve the problems, the clamp mechanism is configured such that the holding arm is provided with a slant part that is slant upward against a face of the disk clamped, and the slant part is engaged with the flange part to lift up the clamper.
As the fourth means to solve the problems, the clamp mechanism is configured such that the holding arm is placed to be swingable in a transverse direction against a moving direction of the clamper.
As the fifth means to solve the problems, the clamp mechanism is configured with, in addition to the first means, a drive gear turned by a motor and a clamp lever turned by the drive gear which is associated with lifting movement of the turntable, wherein the clamp lever is formed integrally with the holding arm.